package com.itheima.apidemo;

import com.itheima.domain.Student;

import java.util.Objects;

public class Demo05 {

    public static void main(String[] args) {
        Student s=null;
        System.out.println(Objects.isNull(s));
        System.out.println(s==null);
        System.out.println(Objects.nonNull(s));
        System.out.println(s!=null);

        System.out.println(Objects.toString(s));
       // System.out.println(s.toString());
        System.out.println(Objects.toString(s,"默认值"));

    }
}
